quantity of mercury, and then pass an electric current through the tube, a vapor is formed by the mercury which not only conducts electric current but produces a number of the most extraordinary phenomena. He discovered, He discovered, furthermore, that if the tube were connected with the wires of an ordinary telephone it would produce a loud roaring sound which made it utterly impossible for persons to hear each other speaking over the wire. To overcome this great roaring sound was his big problem.

"I finally made the tube keep still," he said. in a matter-of-fact way. "I did it by exceedingly careful adjustment of an inductance and a resistance coil through which the wire from the positive electrode passed to the battery, and by altering the shape of the tube until I had gotten the positive electrode a certain distance from the negative electrode, just about a quarter of an inch, and by making the negative electrode of a fine platinum point protruding the fraction of an inch above the mercury and capped with at tiny bit of mercury. Even then it wouldn't work right until I made the positive electrode in the shape of a small disk with a hole in its center and placed the platinum needle directly under the hole. I then found that the current spread from all parts of the pierced positive disk simultaneously and entered the tiny platinum point smoothly and noiselessly, and that the problem

PETER COOPER HEWITT

purposes bears his name.

with any but alternating current-is transformed into a smooth, direct current on passing through the vapor. A fierce, jerky current enters the little tube. A smoothly flowing current comes out. There's the secret of it."

The sending apparatus is based on the same principle as the receiving, both depending on the mercury vapor tube, but the receiving changes direct to alternating current. Our telephones are operated with direct current, and for that reason no sounds interfere with the conversation. If alternating current were used it would have to vibrate so rapidly that it could not be heard by the human ear. High C, which the human voice rarely reaches, has a sound frequency of 1500, or has 1500 vibrations or waves, to the second. Sound goes higher and higher with increased frequency until it vanishes.

"Wireless telegraphy was possible before wireless telephony," said Mr. Hewitt, "because the first instruments invented to create a high frequency gave off their waves in 'trains,' or series of four or five waves each, and therefore could not carry a continuous sound but could carry dots and dashes. The vapor tube, unlike the carbon arcs in use, lasts practically indefinitely, with no part of it burning out, and the frequency of the current can be readily adjusted without interrupting the conversation. This is what has retarded wireless telephony. The tube can alter the frequency from zero to one hundred thousand waves per second. The wave frequency of the largest wireless telegraph stations at present is thirty thousand, making each sound wave six miles long-thirty thousand of them passing a given point in a second. The wireless telephone in combination with the mercury tube probably will use about the same frequency."

Distance will make practically no difference whatsoever, because of the power of the instrument to pick up the

music will in no way interfere with its workings-in fact, it registers the human voice in the same accent and tone in which it is uttered. For sea and air use, for ocean liners or for Zeppelins, it will accomplish its end with an equipment lighter and smaller than the telegraphic instruments now in use.

"The intercepting of a message in war would be fatal," said he, "and effort to use a code over a telephone wire would be cumbersome. But by virtue. of the fact that the apparatus can be adjusted to send and receive extremely high wave lengths, and that both sender and receiver can be attuned to harmonize with one another and not with outside instruments by adjusting the wave lengths, it will be possible to send messages from one point to another so that they can be heard only. through the instrument they are intended for."

The same receiver is used for both wireless telegraphy and wireless telephony.

"For experimental purposes," Mr. Hewitt said, "just at the present moment we are catching all the wireless telegraph messages in the air about New York on that instrument on the table." He pointed to the little vacuum tube, and to the telephone headpiece attached to it. When this was adjusted to the head, sounds such as emanate from wireless telegraph rooms could be heard. There were two receivers working and the inventor put one to his head. He pushed a switch around. a few notches and the sounds could be heard with greater distinctnesspossibly, the inventor said, more distinctly than the operator who was taking the message heard them. The switch was reversed, and a confusion of messages could be heard, one buzzing indistinctly, another a bit clearer, another as clear as the ticking. of a clock nearby. As the switch was moved from notch to notch, each message altered in distinctness. The in

T

HE clash of Man versus Nature at the mouth of the Columbia has been almost continuous for the past thirty years and more. Man recognizes the Columbia as one of the greatest natural highways of the continent and, with a single exception, commercially the most important stream within our national borders. The completed south jetty and the uncompleted north jetty might be called stupendous breast works, erected in the daring attempt to compel the river to carry its gathered silt and sand on into the deep water of the ocean, rather than to permit it to drop this sand and spread it fan-like over an ever widening and ever shallowing delta. At its mouth, the Columbia broadens to about ten miles. Here, the ocean winds and waves and currents periodically drive inshore to clash with the force

of the river, which tends to precipitate and to shift its carried sand and silt. Thus, the river channel across the ocean bar is really in a struggle with the forces of the sea to maintain itself. This river channel, unfettered by man, is continually changing, creeping back and forth, snake-like, shifting its coils some two or three thousand feet each year.

The struggle, the action and the reaction of the ocean and the river are titanic, because the old Pacific, at this point, is a drastic war lord. To this. fact many wrecked ocean vessels could testify. For instance, there was the Rosecrans, which was battered into nothingness at a point near the north jetty, now being built. Thirty-three of the thirty-five members of the Rosecrans' crew went down, the surviving two being rescued only at the repeated risk of the lives of two United States

life-saving crews, hundreds of persons watching the battle from the promontory in the background.

Out on the lightship that guides the way to the mouth of the Columbia during storms the vessel is forced to keep up full steam against the wind to insure that the strongest possible anchors do not tear loose. Also, the keepers of the Tillamook Head lighthouse, not many miles to the south, could tell of the times when waves have beat over the top of their beacon, one hundred and thirty-two feet above the normal water level.

On the south jetty the diminutive rock trains dash along on toy-like three-foot-wide tracks. Sometimes the dumping or the chance falling of the great four- to twenty-ton rocks that are used to build up the sea wall derails the cars. Thus one entire train was lost off the south jetty. The fireman and the engineer of the train saw in time. Both jumped from the engine when the cars began to turn turtle. The fireman had the presence of mind to leap to the side, over an open space on to the second parallel return track.

The engineer barely had time to leave his cab; at least.so he thought. He alighted ahead of his engine, which was still moving rapidly. He raced for his life along the track, not remembering whether he had opened or closed the throttle as he jumped, and not daring to take time to look around. Of course he did not realize that the joke was on him until after he had covered almost a mile in record time and had charged into the pile-driver at the very front, the "boys" on the pile-driver being so unsympathetic as to laugh when explanations were made and no engine. or train was in sight.